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Problems
Contests
National and Regional Contests
Turkey Contests
National Olympiad First Round
2005 National Olympiad First Round
25
25
Part of
2005 National Olympiad First Round
Problems
(1)
P25 [Geometry] - Turkish NMO 1st Round - 2005
Source:
10/26/2013
Let
E
E
E
,
F
F
F
,
G
G
G
be points on sides
[
A
B
]
[AB]
[
A
B
]
,
[
B
C
]
[BC]
[
BC
]
,
[
C
D
]
[CD]
[
C
D
]
of the rectangle
A
B
C
D
ABCD
A
BC
D
, respectively, such that
∣
B
F
∣
=
∣
F
Q
∣
|BF|=|FQ|
∣
BF
∣
=
∣
FQ
∣
,
m
(
F
G
E
^
)
=
9
0
∘
m(\widehat{FGE})=90^\circ
m
(
FGE
)
=
9
0
∘
,
∣
B
C
∣
=
4
3
/
5
|BC|=4\sqrt 3 / 5
∣
BC
∣
=
4
3
/5
, and
∣
E
F
∣
=
5
|EF|=\sqrt 5
∣
EF
∣
=
5
. What is
∣
B
F
∣
|BF|
∣
BF
∣
?
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
A
)
<
/
s
p
a
n
>
10
−
2
2
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
B
)
<
/
s
p
a
n
>
3
−
1
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
C
)
<
/
s
p
a
n
>
3
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
D
)
<
/
s
p
a
n
>
11
−
3
2
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
E
)
<
/
s
p
a
n
>
1
<span class='latex-bold'>(A)</span>\ \dfrac{\sqrt{10} - \sqrt{2}}{2} \qquad<span class='latex-bold'>(B)</span>\ \sqrt 3 -1 \qquad<span class='latex-bold'>(C)</span>\ \sqrt 3 \qquad<span class='latex-bold'>(D)</span>\ \dfrac{\sqrt{11} - \sqrt{3}}{2} \qquad<span class='latex-bold'>(E)</span>\ 1
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
A
)
<
/
s
p
an
>
2
10
−
2
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
B
)
<
/
s
p
an
>
3
−
1
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
C
)
<
/
s
p
an
>
3
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
D
)
<
/
s
p
an
>
2
11
−
3
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
E
)
<
/
s
p
an
>
1
geometry
rectangle